Question

我有这样的查询：

SELECT
        result.ip,
        ips.ipStatus,
        result.quantity,
        result.clickDates,
    FROM
        ips
    INNER JOIN
        (
            SELECT
                visits.ip,
                count(visits.ip) AS quantity,
                GROUP_CONCAT(clicks.clickDate) AS clickDates,
            FROM
                visits
            INNER JOIN
                clicks 
                    ON visits.id = clicks.id 
            WHERE
                clicks.clickDate BETWEEN 1 AND 10 
            GROUP BY
                visits.ip 
            ORDER BY
                null
        ) AS result 
            ON ips.ip = result.ip LIMIT 6, 2

它产生如下结果表：

   ip    |    status    |    quantity    |       date 

1.1.1.1        ok               3            555, 557, 558
2.2.2.2        ok               1            657

我的日期存储在.ms（BIGINT）中。我的目标是要ORDER BY与DESC约会。我想最新的ips将位于顶部。因此，我正在尝试更改ORDER BY上的ORDER BY clicks.clickDate DESC。但这给了我一个错误：

ORDER BY子句的表达式＃1不在GROUP BY子句中，并且包含非聚合列

所以我有两个问题：

如果我在clicks.clickDate列上使用ORDER BY，是否可以GROUP_CONCAT？也许有一种方法可以只显示clicks.clickDate在GROUP_CONCAT之后的最后一个值？

Answer 1

对于主查询order by，您可以尝试在GROUP_CONCAT中添加MAX(clicks.clickDate)并添加一列clickDate，以在组中获得order by的最大值。

SELECT
    result.ip,
    ips.ipStatus,
    result.quantity,
    result.clickDates,
FROM
    ips
INNER JOIN
    (
        SELECT
            visits.ip,
            count(visits.ip) AS quantity,
            GROUP_CONCAT(clicks.clickDate ORDER BY clicks.clickDate desc) AS clickDates,
            MAX(clicks.clickDate) maxDt
        FROM
            visits
        INNER JOIN
            clicks 
                ON visits.id = clicks.id 
        WHERE
            clicks.clickDate BETWEEN 1 AND 10 
        GROUP BY
            visits.ip 
    ) AS result 
        ON ips.ip = result.ip 
ORDER BY maxDt DESC
LIMIT 6, 2

Answer 2

请尝试按每个记录中的最大单击日期进行排序。请注意，我们需要将文本日期数值投射为实际整数，以便排序正常进行。

SELECT
    r.ip,
    i.ipStatus,
    r.quantity,
    r.clickDates,
FROM ips i
INNER JOIN
(
    SELECT
        visits.ip,
        count(visits.ip) AS quantity,
        GROUP_CONCAT(clicks.clickDate ORDER BY clicks.clickDate desc) AS clickDates,
        MAX(CAST clicks.clickDate AS UNSIGNED) maxDt
    FROM
        visits
    INNER JOIN
        clicks 
            ON visits.id = clicks.id 
    WHERE
        clicks.clickDate BETWEEN 1 AND 10 
    GROUP BY
        visits.ip 
) r
    ON i.ip = r.ip 
ORDER BY maxDt DESC
LIMIT 6, 2;

如何使用JOIN语句订购DESC？

2 个答案: